The leukotrienes constitute a group of locally acting hormones, produced in living systems from arachidonic acid. The major leukotrienes are Leukotriene B.sub.4 (abbreviated at LTB.sub.4), LTC.sub.4, LTD.sub.4, and LTE.sub.4. The biosynthesis of these leukotrienes begins with the action of the enzyme 5-lipoxygenase on arachidonic acid to produce the epoxide known as Leukotriene A.sub.4 (LTA.sub.4), which is converted to the other leukotrienes by subsequent enzymatic steps. Further details of the biosynthesis as well as the metabolism of the leukotrienes are to be found in the book Leukotrienes and Lipoxygenases, ed. J. Rokach, Elsevier, Amsterdam (1989). The actions of the leukotrienes in living systems and their contribution to various diseases states are also discussed in the book by Rokach.
European patent application 375,404 (Jun. 27, 1990) describes certain naphthalene-containing heterocyclic ethers of structure A which are inhibitors of the enzyme 5-lipoxygenase. EP application 375,452 (Jun. 27, 1990) describes naphthalene-containing hydrocarbon ethers of structure B which are reported to possess the same activity. EP application 462,830 (Dec. 27, 1991) describes bicyclic heterocycle-containing hydrocarbon ethers of structure C which are reported to possess the same activity. All these series of prior art compounds differ significantly from the present invention in that they lack both the aryl substituent and the additional fused ring of the present compounds.
A series of natural products known as the justicidins are referred to in the Merck Index, 11.sup.th edition, 1989, no. 5154. The justicidins differ considerably from the present compounds in that they are lacking the large pyranylphenyl group.
Hence the compounds of the present invention are completely novel and unexpectedly have biological activity as leukotriene biosynthesis inhibitors. ##STR2##